As a system for detecting an obstacle which dashes into a front area of a moving object such as a vehicle, there is a system in which a single TV camera is mounted to a vehicle to detect an obstacle from an image picked up by the TV camera.
For example, in JP-A-8-249597 incorporated by reference, the obstacle is detected by focusing on variation of the number of edge points on a road surface. In this system, it is considered that an obstacle exists when the maximum number of edge points in a preset certain area reaches a certain threshold value.
However, in the system disclosed in JP-A-8-249597, since the obstacle is detected from the number of edge points, there is a possibility that the obstacle is detected erroneously since the number of edge points increases when there is a pattern drawn on the road surface even though there is no obstacle.